SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1788, 1697, 1657, 1687, 1921, 1238, 1197, 
    1307, 1306, 1940, 1941, 1660
  )

Query time 0.00087

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": 12,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1788,1697,1657,1687,1921,1238,1197,1307,1306,1940,1941,1660)"
    }
  }
}