This file is for your user and only your user, not the user the telegraf service runs as. You need to pass those env. variables to the telegraf user service as well.
One way is to add these to /etc/systemd/system/telegraf.service.d/myenv.conf for example:
[Service]
Environment="INFLUX_TOKEN=foobar"
Environment="INFLUX_ORG=foobar"
edit: there is some additional examples here: systemd.service
