SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c3c4f67dc3c30d04198872fd7b26e2ab32635f4042eb500e76cfc694a81071' 
  AND token = 'wdk7rSu+wjV+kgLM6RNjyJw5zQIN+pgxumu4pjMq8hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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