"They're not birds!" Harry said suddenly. "They're keys! Winged keys -- look carefully. So that must mean..." he looked around the chamber while the other two squinted up at the flock of keys. "... yes -- look! Broomsticks! We've got to catch the key to the door!" (Harry Potter and the Philosopher's Stone, Chapter 16, Through the Trapdoor).
Is there any canon information as to why Hermione didn't just Accio the proper key, avoiding the necessity of flying all over the room to catch it?
Were the keys charmed to not be accioable?
Was it a spell too advanced for even Hermione during First Year? (I didn't see a single instance of its use in HP1).
Was it impossible to Accio a specific key in a room full of them?
I'm looking for a canon in-universe explanation only (e.g. books/JKR interviews/pottermore).
As a note, a simple guess of "Accio wasn't invented till Book N" is not a good enough reason - JKR explicitly stated that she had the details of many books and the universe planned far ahead while writing the first one.
 It's obvious what the reason is from 4th wall perspective (Harry got to show off his 3L337 Quidditch Mad Skillz, just like Ron and Hermione did on "their" tasks)