So I followed the steps described in Williams article.
Boot up vCenter Server using a current Linux live CD. I am using a Ubuntu ISO that I had.
Mount the VMware vCenter Server Appliance root partition. This should be /dev/sda3
Edit the /etc/shadow file with your favorite editor. Advice make a copy of the shadow file before editing it.
When the root password is expired there should be an x in front of the password string. This was the case
Remove the x in front of the password string and save the shadow file.
Reboot the VCSA. If everything went well you are able to logon with the root account.
I was able to logon into the appliance again, but to prevent future problems with the password expiration I disabled the expiration in the management page of the VCSA. Because this is my home lab this is ok.
In production environments this is not advisable
Configure a SMTP server and an alert email account so you will be notified when the password is going to be expired.
Or in a home lab environment, disable the expiration date of the root password.