SELECT 
  SQL_CALC_FOUND_ROWS (
    CASE WHEN products.parent_product_id <> 0 THEN products.parent_product_id ELSE products.product_id END
  ) AS product_id, 
  descr1.product as product, 
  companies.company as company_name, 
  GROUP_CONCAT(
    products.product_id 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS product_ids, 
  GROUP_CONCAT(
    products.product_type 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS product_types, 
  GROUP_CONCAT(
    products.parent_product_id 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS parent_product_ids, 
  products.product_type, 
  products.parent_product_id, 
  products.master_product_offers_count, 
  products.master_product_id, 
  products.company_id 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'ru' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN cscart_warehouses_sum_products_amount as war_sum_amount ON war_sum_amount.product_id = products.product_id 
  LEFT JOIN cscart_warehouses_destination_products_amount AS warehouses_destination_products_amount ON warehouses_destination_products_amount.product_id = products.product_id 
  AND warehouses_destination_products_amount.destination_id = 115 
  AND warehouses_destination_products_amount.storefront_id = 0 
  LEFT JOIN cscart_master_products_storefront_offers_count AS master_products_storefront_offers_count ON master_products_storefront_offers_count.product_id = products.product_id 
  AND master_products_storefront_offers_count.storefront_id = 1 
WHERE 
  1 
  AND cscart_categories.category_id IN (
    304, 1201, 315, 318, 311, 314, 310, 316, 
    309, 317, 319, 312, 313, 308
  ) 
  AND (
    companies.status IN ('A') 
    OR products.company_id = 0
  ) 
  AND (
    (
      CASE products.is_stock_split_by_warehouses WHEN 'Y' THEN warehouses_destination_products_amount.amount ELSE products.amount END
    ) > 0 
    OR products.tracking = 'D'
  ) 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND products.master_product_status IN ('A') 
  AND products.master_product_id = 0 
  AND (
    products.company_id > 0 
    OR (
      master_products_storefront_offers_count.count > 0
    )
  ) 
  AND products.product_type != 'D' 
GROUP BY 
  product_id 
ORDER BY 
  product asc, 
  products.product_id ASC 
LIMIT 
  312, 24

Query time 0.02006

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "descr1.product, products.product_id",
      "temporary_table": {
        "filesort": {
          "sort_key": "case when products.parent_product_id <> 0 then products.parent_product_id else products.product_id end",
          "temporary_table": {
            "table": {
              "table_name": "master_products_storefront_offers_count",
              "access_type": "system",
              "possible_keys": ["PRIMARY", "idx_storefront_id"],
              "rows": 0,
              "filtered": 0,
              "const_row_not_found": true
            },
            "table": {
              "table_name": "cscart_categories",
              "access_type": "range",
              "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["category_id"],
              "rows": 14,
              "filtered": 100,
              "index_condition": "cscart_categories.category_id in (304,1201,315,318,311,314,310,316,309,317,319,312,313,308)",
              "attached_condition": "(cscart_categories.usergroup_ids = '' or find_in_set(0,cscart_categories.usergroup_ids) or find_in_set(1,cscart_categories.usergroup_ids)) and cscart_categories.`status` in ('A','H') and cscart_categories.storefront_id in (0,1)"
            },
            "table": {
              "table_name": "products_categories",
              "access_type": "ref",
              "possible_keys": ["PRIMARY", "pt"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["category_id"],
              "ref": ["admin_test.cscart_categories.category_id"],
              "rows": 13,
              "filtered": 100,
              "using_index": true
            },
            "table": {
              "table_name": "products",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "status", "idx_master_product_id"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["admin_test.products_categories.product_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "products.master_product_id = 0 and (products.usergroup_ids = '' or find_in_set(0,products.usergroup_ids) or find_in_set(1,products.usergroup_ids)) and products.`status` = 'A' and products.master_product_status = 'A' and products.company_id > 0 and products.product_type <> 'D'"
            },
            "table": {
              "table_name": "war_sum_amount",
              "access_type": "ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["admin_test.products_categories.product_id"],
              "rows": 1,
              "filtered": 100,
              "using_index": true
            },
            "table": {
              "table_name": "descr1",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "product_id"],
              "key": "PRIMARY",
              "key_length": "9",
              "used_key_parts": ["product_id", "lang_code"],
              "ref": ["admin_test.products_categories.product_id", "const"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(descr1.lang_code = 'ru')"
            },
            "table": {
              "table_name": "prices",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "usergroup",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["admin_test.products_categories.product_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "prices.lower_limit = 1 and prices.usergroup_id in (0,0,1)",
              "using_index": true
            },
            "table": {
              "table_name": "companies",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "4",
              "used_key_parts": ["company_id"],
              "ref": ["admin_test.products.company_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(companies.`status` = 'A' or products.company_id = 0)"
            },
            "table": {
              "table_name": "warehouses_destination_products_amount",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "idx_storefront_id"],
              "key": "PRIMARY",
              "key_length": "9",
              "used_key_parts": ["product_id", "destination_id", "storefront_id"],
              "ref": [
                "admin_test.products_categories.product_id",
                "const",
                "const"
              ],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond((case products.is_stock_split_by_warehouses when 'Y' then warehouses_destination_products_amount.amount else products.amount end) > 0 or products.tracking = 'D')"
            }
          }
        }
      }
    }
  }
}