Messi, pretty comfortably.
I mean, what he's doing is freaking unreal. His 4 Ballon d'Ors and having 3 CL titles and 5 liga titles at his age

While scoring goals at an incredible pace.
I agree with dude saying he's basically breaking Wilt Chamberlain type of soccer records. His 50 goals in a season in spain is unbreakable, unless he does it himself. The season is 38 games, to score 50 is

.
The original Ronaldo was known to be probably the best scorer of all-time. In professional games with his national team and club teams he scored 466 goals in 677 games.
Messi has scored 320 goals in 432 games

and he hasn't even reached his prime
At this pace he will pass the original Ronaldo in goals scored less than two years, he'll be 27 just entering his prime and already outscored the GOAT scorer
