I believe the key door locks only actuate the electrical door lock. Therefore, if you have a dead battery, they won't work.
What you can do is take off one of the rear light lenses, either tail light or license light, and the bulb. Hook up a 12v battery to the leads of the light. MAKE SURE THE + AND - ARE CORRECT.
Then you can use your key in the door.
2004 Z06 Procharged 525rwhp, 2004 Infiniti G35, 2005 Dodge Ram Daytona, 2007 Lexus IS250, 1999 SLK230