Some things that might help (I'm not an expert or anything!) if you haven't done them already:

I forget what this exercise is called (kikopup has a video on it), but it's similar to training leave it. You should start with your hand closed on the treats. If your dog hasn't seen this before he will try to gnaw his way through your hand for a while then eventually he'll look at you like "wtf?". You click and give him a treat from your other hand. Continue you do this until he gets it, then slowly start opening your hand and doing this in increments. Eventually you should be able to leave your hand open without him going for it. You should start increasing the distance from yourself (so he is tempted to get the food before you do). It's extremely important while doing this to never let him get it before you do.

Training calmness. Kikopup has a video on this as well. Basically when you are watching tv or doing something not paying attention to him, randomly give him a treat for sitting calmly. Eventually he'll pick up on this and sit calmly to try and get the treat. You can tell when this happens because he'll keep darting his eyes back to you checking for treats. You need to make sure it's unexpected. In addition to teaching calmness, this could help teach your dog that treats don't ALWAYS come after a trick. This activity should be done WITHOUT a clicker. Crazy.

Something that works for some dogs too is to use other rewards. My dog looooooves attention, like ears scratches. Sometimes his reward is a big 'good dog!!! oh you're such a good dog!!!!' with a bunch of ear rubs, and that is enough for him. This can then be used in place of treats when you're not doing official training times. Other dogs are motivated by toys so that could be something to try too.

You could also try to increase the frequency of his training. Don't set up a schedule, or make it obvious that you're getting your training gear on (ie, my dog recognizes my treat pouch and gets waaaay too excited). Keep a baggy in your pocket around the house, or maybe in a side table drawer, and randomly quiz him. If he never knows when he's going to need to do a trick and get rewarded, he will take his chances in the future when a reward might not be involved.

Aaaanyways, not an expert by any means, but these are still good things to try with your dog even if they don't necessarily fix your original problem. GOOD LUCK!!!