High use of resources with low visits

I have a server in the DO with EE and running only 1 site, without sending emails and without any other item running.
The site (e-commerce) has an average of 50 visits/day and the settings:

Nginx configuration wp wpfc (enabled)
PHP Version 7.0
HHVM disabled
SSL disabled

All plugins are compatible with PHP 7.0

However, php-fpm5.6 (www-data) has high consumption at various times (image below represents only 24 hours) and these peaks do not represent moments of intense traffic.

How can I identify what is affecting both performance? How can I fix this? Do I need to do any configuration in EE so that it does not happen?

Perhaps your site is under some kind of attack?

Take a look at your access logs, search for .php script calls:

cd /var/log/nginx
grep -w php *.access.log

I haven’t identified any item that indicates attacks.

It listed only a few cron jobs, login attempts (but the iThemes plugin blocked from the 5th error) and other post / page / product updates.

Thanks for listening.