How can I efficiently check the originality of my work?
Ask people

Doing literature research on your own is necessary, and you should spend some time on this to make sure that the result is not already available. But there is only so much you can find, and it often happens that the result has previously been published with a different name or title, which you could not have known about. More experienced people in the field might have come across those works and know that your result is not new.

So ask people in the field that you can trust. Your supervisor/boss/similar is usually a good start. You can also ask other people in your department. As you advance in your career, you often make new contacts with whom you can discuss such things. And, as you have experienced, peer reviewers will provide an additional "safety check". 

Of course, make sure you only ask people who you can trust that they will keep your work confidential. If you are at the beginning of your career, your supervisor might provide further guidance on this.