This isn't a sign of anything to be concerned about.
As a general rule of thumb you should expect to find all kinds of strange URLs in your logs. This is the normal "background noise" of the internet. In essence, shortly after a server becomes accessible to the internet, automated bots will automatically start scanning it for any number of well known security vulnerabilities. In short, if you were to nuke your server from orbit anytime something strange showed up in your logs, you'd have terrible uptime. 99% of the time the exploits that are being attempted are not even applicable to your particular technology/framework.
In this particular case this doesn't even look especially harmful, although it is possible it is targeting some vulnerability that isn't the usual SQLi or XSS vulnerability.
I would say the main take away from this should be that good application security is very important on the internet, but you certainly don't have any reason to worry on the basis of just this.