SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c15b8221c69802832dc91af3c4a921af8dae906ee24a96fb3927ab7d9fdd7849' 
  AND token = 'sI+ZZMvXj0TgbHEKf0gkX6w0bJ4PWLfc3GDYup2Bb4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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