SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    13012, 10759, 10760, 10761, 10762, 10763, 
    10764, 10765, 10766, 9874, 9875, 9887, 
    9879, 9796, 9942, 9943
  )

Query time 0.00039

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": 16,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (13012,10759,10760,10761,10762,10763,10764,10765,10766,9874,9875,9887,9879,9796,9942,9943)"
    }
  }
}