Use a VPN (openvpn), and attach sshd to your VPN subnet instead of using 0.0.0.0 or your publicly routable IP. This is also great for any other services you might want to administer remotely. It's normal to bind your database/cache to 127.0.0.1, but you can also bind to an IP in your VPN subnet, which makes it a little easier than tunneling through SSH to access your database.