mysql/node.js - throw error when deleting a record that does not exist

I am trying to delete a record using an SQL Delete statement and trying to find any record with a 'conkey' of a specific value that is entered in a form.

My code:

  var sqlQueryCommand = 'DELETE FROM `DATABASE`.`CON_LOOKUP` WHERE conkey=' + connection.escape(req.body.conkey);
        applogger.info('sqlQueryCommand: ' + sqlQueryCommand);
            connection2.connect(function(err){
                if(err && jslog == 1){
                    logger.debug('Connection 2 Error:' + err);
                 }
            });


                connection2.query(sqlQueryCommand, function(match_err_QC, results) 
                    { 

                    //  Check for error from SQL
                    if (match_err_QC) throw match_err_QC;     
                    else{
                        var response_json = {
                          "app": appname,
                          "response_code": "1",
                          "conkey": connection.escape(req.body.conkey),
                          "response": "success"
                        };
                        var response_text = JSON.stringify(response_json);
                        response.writeHead(200, {
                          'Content-Length': response_text.length,
                          'Content-Type': 'text/plain' });
                        response.write(response_text);
                        response.end();
                   }

                 });

When I enter a 'conkey' that does not exist in the database, it does not throw an error.

I'm not sure if I should be checking for the record(s) first then deleting them, or just add a piece to my code.

Any help is appreciated. :)