Detect When a Key is pressed, but NOT a mouse click

I am creating a custom sound for whenever a key is pressed, to simulate an old typing sound effect in C#.
However, I can’t find a way to completely ignore mouse clicks, so that only pressing keyboard keys will activate the sound.
If anyone could help me with that, I’d really appreciate it.

Try this:

        void Update()
            if (Input.anyKeyDown)
                if (Input.GetMouseButtonDown(0) 
                || Input.GetMouseButtonDown(1)
                || Input.GetMouseButtonDown(2))
                    return; //Do Nothing
                // Play sound

if (Input.anyKeyDown) {
if (Input.GetKey(KeyCode.Mouse0) || Input.GetKey(KeyCode.Mouse1)) {
else {
// Do stuff.