SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b915c4d0a2f800f3ed3017d7a0e1f9af8fc9452a5e04839c778138fa0201a4f' 
  AND token = 'yL0vr25A//d5nBpOyH6IxATEodCAN50Zu4DgRPwmEDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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