Выполняю отдельно php /home/bitrix/ext_www/art-code.su/cron/script.php, работает.
Cron работает. Выполнил systemctl status crond.service -l
[bitrix@localhost ~]$ systemctl status crond.service -l
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2017-10-11 16:19:51 EET; 1min 34s ago
Main PID: 543 (crond)
CGroup: /system.slice/crond.service
└─543 /usr/sbin/crond -n
Oct 11 16:19:51 localhost.localdomain systemd[1]: Started Command Scheduler.
Oct 11 16:19:51 localhost.localdomain systemd[1]: Starting Command Scheduler...
Oct 11 16:19:52 localhost.localdomain crond[543]: (CRON) INFO (RANDOM_DELAY will be scaled with factor 45% if used.)
Oct 11 16:19:52 localhost.localdomain crond[543]: (CRON) INFO (running with inotify support)