Most people in the audience reported the pilot as being very good and stylish, but there was also some doubt about the show's longevity. Even the creators admit they burned through many issues of the comic book just to fill out this one episode, so if a series was commissioned it's likely they would perhaps (a) run out of source material too soon, or (b) have to risk audience boredom by spinning their wheels for the majority of season 1, and perhaps beyond.
I haven't read Locke & Key and I haven't seen the pilot, but I get the distinct impression the problem Fox had was nothing to do with the quality of the production, but the long-term potential of the series. Regardless, there are rumblings MTV may be interested in picking up the show. The music channel have been commissioning scripted drama just lately, with Teen Wolf, Skins and Death Valley, so could they soon be adding Locke & Key to that line-up?
However, MTV must surely see the same problems Fox identified, so will they opt for a miniseries continuation? Could Locke & Key even be made on a cable-sized budget? Also, are the pilot's cast and crew still willing and able to return? When a series is refused actors, in particular, are very quick to look for other work, so some key members of the cast might be going other things by now. Would MTV recast people between the Fox pilot and episode 2, or would that be too confusing?
Sorry, but my gut says Locke & Key is dead in the water, because it's just not TV series material. I'm surprised Fox even made a pilot, really, but US networks are like that. Even the trailer plays like a movie trailer to me, not a teaser for a TV series. But hey, if you're a big fan of the graphic novels, you can clutch onto this straw for awhile, until it's probably denied by an MTV spokesman in the next few days...
In the meantime, just enjoy the dead pilot's impressive two-minute trailer:
