SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    12676, 12677, 12678, 12679, 9687, 10024, 
    10025, 10026, 10027, 10028, 10029, 
    10030, 10031, 10032, 10033, 10034, 
    10035, 10036, 10037, 10038
  )

Query time 0.00126

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 (12676,12677,12678,12679,9687,10024,10025,10026,10027,10028,10029,10030,10031,10032,10033,10034,10035,10036,10037,10038)"
    }
  }
}