Tools I can use to find similar genes
I personally do not find the second part with the queries helpful without greater context.

The first part appears to be an accession number (more information on these can be found here: https://www.ncbi.nlm.nih.gov/Sequin/acc.html). By going to NCBI (https://www.ncbi.nlm.nih.gov/) and searching that accession number, you can get a lot of information quickly and easily.  Searching this particular number shows it to be a Asparagine-tRNA ligase from the fungal genus Leucoagaricus (https://www.ncbi.nlm.nih.gov/protein/KXN84633.1/).

If you simply have a DNA or protein sequence and no accession number, you can perform a BLAST (https://blast.ncbi.nlm.nih.gov/Blast.cgi).  This will search your sequence against a massive database of annotated DNA or protein sequences. The specific type of BLAST to run and the ideal parameters will take some reading on your part to determine.  However, if you're just starting out, nucleotide BLAST for DNA sequences, protein BLAST for protein sequences, and default parameters will often suffice. This search will provide you with the best "hits" to the database which you can then follow up on to get an idea of the function of your original sequence.