SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    9879, 9796, 9942, 9943, 9941, 9944, 10813, 
    10814, 10815, 10816, 10817, 10818, 
    10819, 10820, 10821, 10822, 10823, 
    10824, 10825, 10826
  )

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 20,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (9879,9796,9942,9943,9941,9944,10813,10814,10815,10816,10817,10818,10819,10820,10821,10822,10823,10824,10825,10826)"
    }
  }
}