You can view the last connect column under PWA>Server Settings>Manage Users
You can also get this data from the Published database
SELECT RES_NAME, WRES_LAST_CONNECT_DATE, RES_LAST_ACTIVITY
FROM MSP_RESOURCES
WRES_LAST_CONNECT_DATE is a date time stamp of when the user last initiated
a logon to the environment PWA or Project Pro will initiate a new timestamp
here. This is the same date as what you see under the last connect column
under PWA>Server Settings>Manage Users
RES_LAST_ACTIVITY is a date time stamp of when the user last clicked on a
page in PWA or an activity in Project Pro that hits the database.
Disclaimer: Microsoft does not support querying the Published database.
Hope this helps,
Jonathan Sofer