The difference between the two parts is the lead length.
MKP1845422105
https://www.digikey.com/short/z012q5
MKP 220nF ±10% 1000Vdc AXIAL ENCASED , loose packaging
Normal wire length 40±5mm
MKP18454221051
https://www.digikey.com/short/z012qt
220nF ±10% 1000Vdc axial, loose packaging
Special wire length 41+10mm