The speed of the mash is mainly down to enzymatic activity, and this is influenced chiefly by temperature and then by pH. Naturally you don't want to change your temperature, so the next thing is to be sure your pH is within 5.1-5.5 pH.
As well as enzymatic activity, there is the time it takes for the enzymes to leach out of the grains into the mash liquor. A finer crush may help to some degree but I doubt it will anywhere near the 50% reduction you're looking for.
To get any significant reduction, you can skip the 30 minutes at 56C, which is at the top end of a protein rest. Modern malts have had many of the proteins already broken down as part of the germination process - in fact performing a protein rest on these malts can reduce body and head retention. A mash out rest isn't strictly necessary either - it's there to lock in the current sugar profile by denaturing the enzymes to prevent further conversion. The mash out can be combined with the sparge. Cutting both of those rests will reduce your mash by 45 mins.
Lastly, rather than just waiting for the full rest, you could do a starch test with iodine to determine if there are still unconverted starches or not. Pull off a few drops of wort (without grain particles) and add a drop if iodine. If the iodine doesn't turn black, you're done.
Personally, I always do 90 minute mashes, longer for bigger beers. I set enough time aside so that I can give each step the time it needs.