SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    439645, 401030, 435106, 401667, 431036, 
    442622, 435820, 452529, 426624, 403050, 
    452048, 407841
  )

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.0216566,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 12,
          "cost": 0.0216566,
          "filtered": 100,
          "attached_condition": "cscart_products.product_id in (439645,401030,435106,401667,431036,442622,435820,452529,426624,403050,452048,407841)"
        }
      }
    ]
  }
}