Moved from the scripting forum...
There is no command for unlocking a single layer for which you can make a keyboard shortcut. There is a command to unlock all layers, but i has no default shortcut, so you'd need to create your own.
You can assign a keyboard shortcut to a script.
So you could take this, change the name of the layer (here: "Layer 2") to the name of the layer you want to unlock, save it and assign your own shortcut to "I want to unlock layer 2".
app.activeDocument.layers.item("Layer 2").locked = !app.activeDocument.layers.item("Layer 2").locked;
If this doesn’t help we'd need to know what exactly you are trying to do.