SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    7637, 8883, 8384, 8385, 8896, 8881, 8826, 
    7811, 7809, 7810, 7808, 7807, 8882, 
    7696, 7403, 8847, 8825, 7898
  )

Query time 0.00074

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_warehouses_sum_products_amount",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 22,
      "filtered": 100,
      "index_condition": "cscart_warehouses_sum_products_amount.product_id in (7637,8883,8384,8385,8896,8881,8826,7811,7809,7810,7808,7807,8882,7696,7403,8847,8825,7898)"
    }
  }
}