Welcome to the Community,
which edition did you register? The free Hypervisor or vSphere Evaluation? If you got a license key, I think you registered for the free Hypervisor, which - after applying the license key - will run without any time limit. To enter the license key in the vSphere Client, select the host on the left, then click the Configuration tab and enter the license key clicking the Edit link in Licensed Features.
André
