APNS Token based authentication with multiple servers

Question

I’m implementing APNS Token based authentication using pushy Java library right now but there is one unclear part in Apple’s and Pushy’s documentions.

I will have several severs sending push notifications with pushy using Token based authentication.

What’s troubling me is the part in Apple documentation stating:

For security, APNs requires you to refresh your token regularly. Refresh your token no more than once every 20 minutes and no less than once every 60 minutes. APNs rejects any request whose token contains a timestamp that is more than one hour old. Similarly, APNs reports an error if you recreate your tokens more than once every 20 minutes. 

So the part that I’m afraid is the “no more than once every 20 minutes”. If I have let’s say 4 severs and each generate a token every 50 minutes using the same signing key, will I be constantly in this limit? Unless this limit applies to each TLS connection maybe. Do I have to build a way to share tokens across servers, if so can Pushy be configured with a token directly? or should I use a different signing key for each server?