SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    321, 320, 319, 318, 317, 316, 315, 314, 
    313, 312, 311, 310, 309, 308, 307, 306, 
    305, 304, 303, 302, 301, 300, 299, 298, 
    297, 296, 295, 294, 293, 292, 291
  )

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "ALL",
          "possible_keys": ["PRIMARY"],
          "rows": 53,
          "filtered": 58.49056625,
          "attached_condition": "cscart_products.product_id in (321,320,319,318,317,316,315,314,313,312,311,310,309,308,307,306,305,304,303,302,301,300,299,298,297,296,295,294,293,292,291)"
        }
      }
    ]
  }
}