Although there is no embedded way in the system to perform this task, you can use either of the following ways:-
1-If you have a call logger, run a report on all extension that have had no call activity over a period of time.
2-Export the maintenance logs, which captures all hotdesk login and logout activities and use the excel export to filter the login attempts and cross reference these with the exported user and configuration form to identify which accounts have not logged in.