My main issue with this is that it would be a little too convenient for beguilers. Wizards, sorcerers and warlocks have to make considerable sacrifices to fully utilize this spell, either by CCing open lock, by taking levels of another class which lowers the DC of the spell (in order to be able to open the lock) , or by sacrificing other spells that are important.
A beguiler on the other hand, would be able to effortlessly lock and unlock any door on a whim through the freedom offered by spontaneous casting. They would end up with high lock DCs with no real sacrifice or investment.
Furthermore, it's an abjuration spell that physically creates or manipulates the lock of a door. It doesn't follow their general theme of enchantment, illusions and hindering enemies through deliberating magic.
TLDR: It would be a fun addition to beguiler, but it would be giving them a lot for no real investment or effort, making them the one sole caster that can effortlessly unlock the highest DC locks that this spell can produce, while also being able to cast it themselves.