BOARD:  Arduino UNO
IDE:    1.8.19
LIB:    0.1.0

examples\I2Ckeypad8x8_demo01\I2Ckeypad8x8_demo01.ino

229100	64	664
229201	64	1324      //  floating lines (no pull ups yet).
229300	64	664

153101	35	1324      //  key pressed ...

A read just takes 664 us.