In the last many flights I have taken, I never took more than 15 min from airport entrance to lounge, except once when I was flying 9w to lhr and they took 15 min to just check me in.
normally I would allocate 5 min max for check in unless flying 9w. security takes less than 2 min. There's are two immigration desks for business class, one for wheelchair and one for diplomats. You should not take more than 5 min there. The walk to the gates is Max 5 min away.
However I make it a point to reach 90 mins before. I really love the gvk lounge and it deserves some time well spent.