SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    8816, 15145, 8808, 7341, 7343, 7342, 
    7344, 10061, 7658, 7873, 7875, 7874, 
    7347, 7833, 7823
  )

Query time 0.00064

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": 16,
      "filtered": 100,
      "index_condition": "cscart_warehouses_sum_products_amount.product_id in (8816,15145,8808,7341,7343,7342,7344,10061,7658,7873,7875,7874,7347,7833,7823)"
    }
  }
}