The 54KYA is Sentinel-2 Tiling ID which can be found in the naming convention. You can also download the Sentinel-2 tiling grid kml here. 54 indicates the UTM zone as you mentioned.
Since the Sentinel-2 tile is 100km x 100km, it can be separated into 100 Sentinel Hub 10km grid tiles and the number 7_1 indicates the row and column of the tile. If you’re interested in the grid you can download it here.
Thanks @chung.horng This has been helpful. I have downloaded the kml file and loaded it to Qgis but it’s not displaying. I was thinking of clipping it to my country of interest and using it. Why is it not displaying in qgis?