Maybe..? It seems possible. Although I'd think any stress would be where your midi keyboard tray attaches to the pull-out arm. However, that might not be a problem if the wood is strong enough. The other potential issue, that depends on your standing desk, is the 23" track that's mounted under the desk top. If your desk has bars going across this area, that's not going to work.

Like what whipdancer mentioned, keyboard drawer slides are probably used by most for this, myself included. You wouldn't want to use a clamp-on version though, all that weight would be on the clamps and desk edge and I'm betting the keyboard would also be bouncing up and down while playing. Slides like these are what I used and worked well as-is for mine, but your keyboard is taller and would require you to add height somehow, possibly like this user did. There are other ways to install the drawer slides and tray; more complicated but also more heavy duty. I can post links to some I've found if you'd like.

Another option to consider is a rolling keyboard stand that slides under the desk.