SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    6516, 6341, 6517, 6600, 6555, 5873, 6159, 
    5495, 5872, 7078, 5491, 5864, 5865, 
    5492, 5493, 5494, 6250, 7041, 6953, 
    6515, 7042, 6160, 18151, 18150
  )

Query time 0.00066

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": 25,
      "filtered": 100,
      "index_condition": "cscart_warehouses_sum_products_amount.product_id in (6516,6341,6517,6600,6555,5873,6159,5495,5872,7078,5491,5864,5865,5492,5493,5494,6250,7041,6953,6515,7042,6160,18151,18150)"
    }
  }
}