Yes, it will be expired after one year. Automatic certificate renewal feature is the default on kubernetes 1.15 version unless you have explicitly disabled it during the kubeadm init phase with --certificate-renewal=false option.

Check expiration:

    kubeadm alpha certs check-expiration

E.g.

CERTIFICATE EXPIRES RESIDUAL TIME EXTERNALLY MANAGED

admin.conf Sep 06, 2020 04:34 UTC 361d no
apiserver Sep 06, 2020 04:34 UTC 361d no
apiserver-etcd-client Sep 06, 2020 04:34 UTC 361d no
apiserver-kubelet-client Sep 06, 2020 04:34 UTC 361d no
controller-manager.conf Sep 06, 2020 04:34 UTC 361d no
etcd-healthcheck-client Sep 06, 2020 04:34 UTC 361d no
etcd-peer Sep 06, 2020 04:34 UTC 361d no
etcd-server Sep 06, 2020 04:34 UTC 361d no
front-proxy-client Sep 06, 2020 04:34 UTC 361d no
scheduler.conf Sep 06, 2020 04:34 UTC 361d no

Renew all certifications:

  kubeadm alpha certs renew all

Renew only admin.conf:

  kubeadm alpha certs renew admin.conf
  cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

This is OAuth provider specific. For example GKE uses this.

So in short, auth provider issues you a JWT token a proof you are auth, which contains a data like expiration time, according to documentation it cannot be more than 60 min in case of google accounts.

I hope it helps.