Lost access to cluster due to admin token expired

HI all
I have lost admin access to my Kubernetes cluster due to expired admin certificate.
" kubectl get nodes
error: You must be logged in to the server (Unauthorized)"

I create this cluster exactly one year ago, but didn’t know that the admin account expires!

How do I recover/generate/update this token, without “kubectl”?

Thanks in advance!

Cluster information:

Kubernetes version: 1.14
Cloud being used: bare-metal
Installation method:
Host OS: Ubuntu 18.04