Almost all of the Angels aren't reef safe, from the small pygmy to the large angels. It's always a crap shoot if they may eat some corals, and it doesn't always happen right away, it can take weeks, months or even a year before they start. So if you willing to take the chance, and can live with it eating one of your corals, go for it.
The Mesoleucus or Singapore angels aren't the easiest to keep, and neither is the Keyhole. If you had a problem keeping the Keyhole you may want to look at one of the more hardier angels before you go with another one that isn't easy to keep, like the Mesoleucus.