SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5259ae90ca13ebf0a88171f44208e4494052fa1bb22ed8730c7e873bcc5cb297' 
  AND token = 'siJgO9qmboWETtoiDrkUes1Wkd2YTIwAqZEUEhlU7rQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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