SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    19899, 20209, 20162, 20163, 20164, 20211, 
    20165, 20210, 20160, 20161, 20017, 
    20018, 20020, 20021, 20022, 20019, 
    19936, 19937, 19938, 19926, 19928, 
    19927, 19956, 19957
  )

Query time 0.00060

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": 24,
      "filtered": 100,
      "index_condition": "cscart_warehouses_sum_products_amount.product_id in (19899,20209,20162,20163,20164,20211,20165,20210,20160,20161,20017,20018,20020,20021,20022,20019,19936,19937,19938,19926,19928,19927,19956,19957)"
    }
  }
}