full text search is not working on live server in laravel

I have added full-text search in my histories table. It is working fine on local machine but on live server is giving error after taking long time. Error is here

504 Gateway Time-out

My migration for full text search

     DB::statement('ALTER TABLE histories ADD FULLTEXT search(model)');
    $table->engine = 'MyISAM';

And this is how i am trying to use it

$histories->whereRaw("MATCH(model) AGAINST(? IN BOOLEAN MODE)", $strtable)

What could be the issue. Please guide full query

$histories->whereRaw("MATCH(model) AGAINST(? IN BOOLEAN MODE)", $strtable)->where('object_id', $po_id);
$histories->orderBy('id', 'desc');

via Chebli Mohamed