CentOS 7 SSH login with Keys Authentication
Yes, but you will first need to log in as the master or root account, and then sudo su otheruser in order to log in as that user. There is no way to log in as any user without first going through a privleged user's account.

An additional caveat is that the user you are trying to log in as needs to have a shell of /bin/bash or similar valid shell in /etc/passwd. If the user has a shell like /bin/fase or /bin/nologin you will be unable to change to this user's account (but neither will anyone else for that matter).