I looked at the game cast from the Pacers/Warriors game. He scored 40 in the first half. And it took him 5 minutes and 21 seconds to score points 41-50 (as in, he scored his 50th point at the 6:39 point of the 3rd quarter).
He scored 10 more points up until 1:22 left in the game (for 5:17 additional minutes).
So he actually scored his 50th point in *less* than 27 minutes by a decent amount (approximately scored his 60th point in 27:52).
SO like I said, FAMS, he did not score 50 points the quickest or in the least amount of time, Klay Thompson did.