if you haven't seen or read the books/movies leading up t this the clones are sped up by the cloners perhaps they stop getting sped up after clone wars?
because the clones of the 501st were not that old in episode 5&6 they used people not clones and some were still supplied from the kaminoans in between episode 3 and 4 and some retired or died others that died during fights and were replaced by newer clones
Near the end of the Clone Wars, one of the Republic Commando's (elite troops), figures out a way to stop the geneticly programmed fast aging in clones, with 'help' from several kidnapped or bribed genetecist or cloners. The Commando's were raised and trained by Mandalorians, and after the war, many of them 'disappear' to Mandalore, where they live normal lives, thanks to this cure. We never see Mandalore in the movies, and indeed, Boba Fett is one of the few Mandalorians stil active in the larger galaxy. Having adopted Mandalorian culture, it would be impossible to recognize the clones afterwards anyways, unless seen without helmets. The particular clone you are refering to has a habit of wearing grey leather gloves, made from the skin of the Kaminoin who developed the meathod to accelerate the clones aging. Episode 2 & 3, clones from Kamino were used by the Galactic Republic. With the end of the war, Palpatine switched production to secret facilites he had built on one of the moons of Coruscant, cutting out the need for aliens in his Xenophobic, sexist regime. At this time, all clones were still pure Jango Fett. Now, the Kaminoins didn't like this. Palpatine, hoping to destroy any hope of any resistance cloning their own army, invaded Kamino, where his army of Clones encountered the Kaminoin army of clones, bred specificly to take on other clones. Eventually, Palpatine won, however, he determined that it was too easy to 'corrupt' an army of clones, so began rotating in regular soldiers, as well as clones of those soldiers.