Yes. Any address that actually resolves the server will give you access to the control panel. Keep in mind that you must have the "s" on https:// (denoting a secure connection) and you must include the trailing port number. An example would be:
https://www.mydomain.com:8443
If www.mydomain.com resolved to a site on the Plesk server, the above URL would take you to the server's login screen.