please check out the following section from the Qlik Sense Online Help
You purchase x number of licenses(tokens). Once you load them onto your installation then you can choose to have them be named user tokens (1 token per user with unlimited logins). Or as login tokens (1 token = 10 logins). Login token are used for people who don't login often. Named user would be developers and such who are in Qlik all of the time. A login token is good for 1 login for 1 hour. Then it is unavailable again for 30 days.
It is a little confusing.