@laravelcode did you ever find a solution to this?

I don't know what was wrong with @laravelcode's code, but he got the right idea--add the check for TokenMismatchException to render method of App\Exception\Handler class, as per documentation.

Here's mine (irrelevant parts skipped):

<?php namespace App\Exceptions;

use Exception;
use Illuminate\Foundation\Exceptions\Handler as ExceptionHandler;
use Illuminate\Session\TokenMismatchException;

class Handler extends ExceptionHandler {
	public function render($request, Exception $e)
	{
		if ($e instanceof TokenMismatchException) {
			return redirect()->back()->with('message', 'Security token expired. Please, repeat your request.');
		}
		return parent::render($request, $e);
	}
}