There is a chance that the wire is there, all you would need to do is plug the 2 wires on the outlet.
You can pick one of those up anywhere, auto parts store, junk yard, the socket is what used to be a cigarette lighter socket.
If the wire isn't there, you can run one from the battery, if you want a full time socket.
If you only want it to work with the key on, you will have to pick a heavy power wire that will support the power you need.
One heavy wire from the power source, then just a short ground wire from the dash structure will be a good ground.