Soft keys enabled covers shortcuts at Lockscreen in Redmi 1s MIUI 8 [Root]
Consider using apps like GMD Full Screen to hide softkeys when not in use (aka Immersive Mode). Or better, just ditch the navbar and use LMT Launcher for the same effect (and more).

As for the lockscreen, since no Xiaomi devices inherently have softkeys, they designed the UI without it in mind, therefore parts of the UI won't adapt to it without undergoing modifications.