SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bf6981982449a98cc4bbb64c54a83fa2d4b3fecdd97e8fa6c9d17f34ad5df35' 
  AND token = 'pk5vlrASsosKWzUW5yoZV5EKLuPCMZYqI+HtZbUgQvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}