She lipsynched throughout the the whole performance, she sounds exactly the same like she does on the studio version and this is the piano version of the song, so it seems live (she sounds the same on both acoustic and piano versions just like on the original).
And this isn't the first time she lipsynched this era:
What do we have here?
Haters mad and pressed saying she can't sing even when she outsings some of the artists they worship everyday.
And now they say she's miming I can not.
Nice performance Taylor.