SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e843ff3b956b9c23446910ccdc849b7505575a451c89777a3ebd8c55e99a43c6' 
  AND token = 'ZmKeiUl5Eb/kkWnSFEiQTaWlq6C1rzwqUTkRFxyQVy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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