How do I expire users credentials for Kubernetes in Azure?
First How to check Check certificate expiration

You can use the kubeadm alpha certs check-expiration command to check when certificates expire on a given cluster.

Simplest remedy : you can choose to upgrade the control plance which will renew the certs and then you are good and secure as before loosing your laptop.

Automatic certificate renewal


  Note : kubeadm renews all the certificates during control plane upgrade.


This feature is designed for addressing the simplest use cases; if you don’t have specific requirements on certificate renewal and perform Kubernetes version upgrades regularly (less than 1 year in between each upgrade), kubeadm will take care of keeping your cluster up to date and reasonably secure.


  Note: It is a best practice to upgrade your cluster frequently in order to stay secure.


Another option is to perform Manual certificate renewal


  Note: The default Kubernetes certificates normally reach their expiration date after one year.


Refer more on kubeadm alpha certs renew command usage.

You probably also need to explore the beta feature for Certificate Rotation