you need to add a user which has the right to access from remote IPs.
in mysql cli do something like
grant select on *.* to remote@'%' identified by 'password';
The port is accessible by default in OVA - if you have Windows, RHEL or CentOS you need to modify the firewall settings accordingly.
Then connect Workbench with this user. With "select" in the example the user has only read rights. Editing may have unexpected results....