In a way, your installation is similar to ours – a wall on the left very near the mixer. We used the long coiled cord for our headphones to go around the back of the mixer to a large hook installed on the wall where the headphones can hang. If your phones have a cord too short, just get a stereo extension cord.
If you search Amazon for a headphones support you will find several options, one of which may work for you. I saw a couple of devices that clip to the tabletop, for example.
Here is one example: Table top clip