Use the following shortcuts to lock and unlock layers in Photoshop.
• Command + / (Mac) | Control + / (Win) toggles between locking and unlocking all selected layers. (Clicking on the lock icon will also unlock a layer).
• Command + Option +/ (Mac) | Control + Alt + / (Win) unlocks all layers (except the Background layer).
• In addition, there is a new menu item Layer> Lock Layers.
Specific to locking Shape layers:
• If a shape layer is locked, it now behaves properly and cannot be selected (in previous versions it could).
• When a Shape layer is locked, the Shape Properties in the Properties panel will be disabled.