Short answer, there's nothing in the book to support replacing your Technology check with your Move Object ranks, so there's nothing in the book to support that idea. So by the book, it is simply your Technology roll. And given Move Object ranks decide how much weight you can lift, not your precision, I honestly don't think extra ranks really make sense for becoming more precise in your movements.
What you can do is to buy Enhanced Skill (Limited to metal objects) alongside your power and use that. Note that, while I don't think there's a canonical addressing of the subject, the general agreement is that Flawed Skills follow the regular power Progression, and one Flaw would bring you to 1 PP / 3 ranks. If you made it also limited to Lockpicking (your character not really being the type to assemble a car engine on the spot), you could readily go to 1 PP / 4 ranks. Because of your ability to sense and move the metal using your powers, it's very cheap to get your Technology (or relevant Expertise skill, such as Expertise (Burglar)) high enough to hit caps, and thereby be one of the best around. 5 PP is enough to provide 20 ranks of Technology, enough to hit caps in a PL 10 game, and enough to be able to open bank vaults as a Routine check.
Side note, as discussed by a few people on the Reddit thread, there's nothing really inherent about picking locks being an Intellect thing. While it's not explicitly stated for other skills (and there are issues of point economy to consider), Expertise explicitly states that you can use other abilities as applicable, so Dexterity wouldn't be out of line.
The ability modifier for Expertise is typically Intellect, but some areas of expertise may call for different abilities, perhaps depending on the task involved. For example, a technical expert might rely on Intellect to answer questions and handle day-to-day procedures, but need Dexterity to perform the actual functions of the job. Performance skills, such as acting or music, may rely on Presence. The GM sets the ability modifier as needed for the specific Expertise check.
I'd also recommend getting either Improvised Tools or a relevant Feature so that you don't need tools for things you can do directly with your power to avoid any penalty.