I actually ran into this problem recently. There is a little hole on the right side of the drive tray door (at least that’s where it was on mine, it might be in a different location on different optical drives). Get a paper clip and bend it so it is straight, hit eject/open and then insert the paperclip in the little hole and gently push. It should release the drive door and let it open. Depending on what is causing the problem, you might have to manually repeat this a few times to “walk” the drive tray far enough out to grab it by hand. In my case, it was just hanging, so as soon as I pushed with the paperclip, it opened normally.