SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f3bd80312476b8a02f08ca7cb233393cb36926ec4db2ee450e5850b9870f241' 
  AND token = 'VLCFZJ+yuTe1Ki1T8HWjVfWUXUw8unDMCZQB7rszrD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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