A single, reasonably tough general purpose BJT is all you need here if you really want a simple solution. The 2N4401 supports up to 600mA of current and has a 40V Vce max. As long as the relaysolenoid on the door lock has a snubber it doesn't need to be any more complicated than this unless you need isolation or have other constraints.
Note that below I've drawn a relay because it was easy, but you can just as well put your door lock's solenoid coil where the relay is drawn below (they're effectively the same type of device).
I have exactly this setup on an ESP8266 controlling a 24V relay and it works great. I'm using an old 2N2222, which are long since obsolete, but the 2N4401 would do just the same.
