SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    4487, 4731, 4754, 4772, 4756, 4476, 4477, 
    4554, 4556, 4558, 4621, 4773, 4703, 
    4623, 4624, 18036, 4757, 4702, 4560, 
    4478, 4774, 4494, 4493, 18037
  )

Query time 0.00072

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": 32,
      "filtered": 100,
      "index_condition": "cscart_warehouses_sum_products_amount.product_id in (4487,4731,4754,4772,4756,4476,4477,4554,4556,4558,4621,4773,4703,4623,4624,18036,4757,4702,4560,4478,4774,4494,4493,18037)"
    }
  }
}