#!/bin/bash
s='TOKEN = decrypt_aes(
"189272123124aqephkiz3")'
sed '/.*decrypt_aes($/{N;s/^\([^=]*=\).*\(".*"\))$/\1 \2/}' <<< "$s"
IyEvYmluL2Jhc2gKcz0nVE9LRU4gPSBkZWNyeXB0X2FlcygKICAgICIxODkyNzIxMjMxMjRhcWVwaGtpejMiKScKCnNlZCAnLy4qZGVjcnlwdF9hZXMoJC97TjtzL15cKFtePV0qPVwpLipcKCIuKiJcKSkkL1wxIFwyL30nIDw8PCAiJHMi