This feature sets a time period in which a token must be activated and utilized. If the token is not utilized for authentication by the user within this time period, the token will not function.
Note that creating the soft token (opening the application and entering the activation code) is not sufficient - the token must be successfully used for authentication within the configured time period. This initial action is how the Defender Security Server is notified that the token has been activated and is within any configured valid activation timeframe.
The properties of the token within Active Directory Users and Computers | Details tab will show a 'Status' line including the date the token must be activated by; or 'Registered' if it has been activated.