Is it a valid use case of using java.util.MissingResourceException?
This is easy to answer: The Exception does not belong to your problem domain. It is not "your" exception. So its use is not appropriate.

Another point to mention is: MissingResourceException is used when the code would expect a static resource provided by a deployment or packaging. Resource-files may be somthing like images or i18n-files. Furthermore configuration-files and everything that is expected to be available in a static way. So your use case does not match the proper usage either.

My suggestion is not to reuse java exceptions that have special usages within the java language unless you are working on the same "abstraction level". You should inherit your own exceptions from "Exception" or far better "RuntimeException" (not signature relevant) and match the exceptions to YOUR problem domain. Everything else is misleading and you have a hard time to identify the proper exception for YOUR context. I do not think that it even exists because of the different abstraction levels. JAVA Exceptions deal with the JAVA language semantics. Everything you do as a developer is nearly always on a higher abstraction level.

JAVA Documentation:

https://docs.oracle.com/javase/7/docs/api/java/util/MissingResourceException.html

https://docs.oracle.com/javase/7/docs/api/java/lang/IllegalStateException.html