Lock Selection

Track View > Curve Editor or Dope Sheet> Highlight keys > Track View toolbar > Lock Selection

Keyboard > SPACEBAR

Lock Selection toggles selection locking on and off. When a selection is locked you can't inadvertently deselect or select anything else. When a selection is locked you don't have to click it to move the keys, you can click anywhere in the window to more or scale the keys.

Note: To use the Spacebar keyboard shortcut, the Keyboard Shortcut Override Toggle must be on.

Procedure

To use Lock Selection in Track View:

In either Dope Sheet or Curve Editor Key window, highlight one or more keys.
On the Track View toolbar, turn on Lock Selection, and then click and drag inside the Track View Key window.

All the selected keys move regardless of where inside the Track View Key window you click and drag.