Cisco CLI command you are looking for is this
service timestamps debug datetime localtime
service timestamps log uptime
It was before like below
1w6d: IP: tableid=0, s=192.168.77.8 (local), d=192.168.77.21 (Vlan77), routed via FIB
1w6d: IP: s=192.168.77.8 (local), d=192.168.77.21 (Vlan77), len 41, sending
1w6d: IP: s=192.168.77.8 (local), d=192.168.77.21 (Vlan77), len 41, sending full packet
After applied above command, now Cisco log timestemp is changed like below
Oct 24 10:09:49: IP: tableid=0, s=192.168.77.8 (local), d=192.168.77.21 (Vlan77), routed via FIB
Oct 24 10:09:49: IP: s=192.168.77.8 (local), d=192.168.77.21 (Vlan77), len 56, sending