It may not be possible to disable it at all, yet a feasible workaround is to increase the execution time. On a nginx tutorial site, it was written:
If you want to increase time-limit for all-sites on your server, you can edit main nginx.conf file:
sudo vim /etc/nginx/nginx.conf
Add following in http{..} section
http {
fastcgi_read_timeout 3000;
proxy_read_timeout 3000;