When you choose align to a key object in Illustrator it automatically selects an object on the higher layer. If I want to select other object I have to select it manually, which is not comfortable when it is small. Is there a hot key combination to switch between two objects?
No, there isn't a hot key for selecting a key object. You'll need to single-click the desired object.
This article says the same:
- select all the objects
- hold ⌘ and click on your key object ("align to" will be changed automatically)