it kinda sounds like something between a castanet and a guiro
castanet - it has a similar resonance but you usually only hear this in 1-4 click sequences
guiro - traditionally it's played more like a washboard to create a rolling percussion, but is much more muted. In the video you linked it does sound more like a stick being dragged across a ridged instrument, but it has a brighter tone and more echo applied.
My first thought was it sounds a bit like the percussion frog, but again, with a brighter pitch:
If the song was played acoustically, I'm not 100%, but if it was created using sound samples, it does sound like the sound made by basic wooden percussion like the claves or castanet, which can then be repeated quickly without needing someone to physically play it that fast.