With dead battery, even my mechanical keys inside our 2 key fobs wouldn't unlock doors initially. See this problem posted often and attributed to design flaw, but on another forum found answer:

https://www.cargurus.com/Cars/Discussion-c3024_ds711107
There I posted:
2011 Nissan Maxima... left accessories on accidentally overnight... dead battery... tried multiple times to unlock with mechanical key w/o luck. Was about to call AAA or locksmith tomorrow then found above "keep jiggling" and "WD40" tips... IT WORKED. After spraying some WD40 into lock and on keys, couldn't turn with my fob key but worked with my wife's. Have to turn CLOCKWISE full 90 degrees. Turned easily actually after sprayed the lube in. Popped hood, jumped after few minutes charging off other running car's battery, then drove around town about 30 minutes in 1 and 2nd gear (sport mode) to recharge. Battery was new just a few months ago so it should be fine now. THANK YOU!