SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    4340, 2364, 13765, 13826, 13993, 2218, 
    2349, 2178, 2177, 11786, 2827, 2640, 
    2312, 2309, 2310, 2311, 3236, 4344, 
    3221, 3225, 3218, 3246, 3222, 4347, 
    3242, 12675, 11361, 12647, 12880, 12670
  )

Query time 0.00049

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": 30,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (4340,2364,13765,13826,13993,2218,2349,2178,2177,11786,2827,2640,2312,2309,2310,2311,3236,4344,3221,3225,3218,3246,3222,4347,3242,12675,11361,12647,12880,12670)"
    }
  }
}