SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_destination_products_amount 
WHERE 
  product_id IN (
    19390, 19391, 16954, 8125, 8126, 7969, 
    8357, 8299, 8879, 8358, 7451, 8671, 
    8242, 8124, 8239, 8376, 8814, 8377, 
    8241, 12403, 8238, 8159, 8240, 8375
  ) 
  AND destination_id = 115 
  AND storefront_id = 0

Query time 0.00186

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_warehouses_destination_products_amount",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "idx_storefront_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "destination_id", "storefront_id"],
      "rows": 24,
      "filtered": 75,
      "index_condition": "cscart_warehouses_destination_products_amount.destination_id = 115 and cscart_warehouses_destination_products_amount.storefront_id = 0 and cscart_warehouses_destination_products_amount.product_id in (19390,19391,16954,8125,8126,7969,8357,8299,8879,8358,7451,8671,8242,8124,8239,8376,8814,8377,8241,12403,8238,8159,8240,8375)"
    }
  }
}