SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    3351, 78822, 3316, 3317, 2512, 3326, 
    3327, 3374, 3331, 3335, 3377, 3376
  )

Query time 0.00035

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 (3351,78822,3316,3317,2512,3326,3327,3374,3331,3335,3377,3376)"
        }
      }
    ]
  }
}