SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    251, 252, 253, 254, 256, 257, 258, 259, 
    260, 261, 262, 263, 264, 265, 266, 267, 
    268, 269, 270, 271, 272, 273, 274, 275
  )

Query time 0.00122

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": 24,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (251,252,253,254,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275)"
    }
  }
}