pdopage как ускорить выборку

{'!pdopage' | snippet: [ 
        'element' => 'msProducts',
        'where' => '{"tvprice_old:="0}',
	        'parents' => $_modx->resource.id, 
	        'limit' => 20, 
	        'pageLimit' => 7,
	        'sortby' => '{"tvqty_msk":"DESC", "tvnal":"DESC"}',
	        'tpl' => 'tableview',
	        'tplPageWrapper' => '@INLINE {$prev}{$pages}{$next}', 
	        'tplPageActive' => '@INLINE <li class="active"><span>{$pageNo}</span></li>',  
        'tplPageNext' => '@INLINE <li><a href="{$href}" aria-label="Next"><span aria-hidden="true">»</span></a></li>',
        'tplPagePrev' => '@INLINE <li><a href="{$href}" aria-label="Previous"><span aria-hidden="true">«</span></a></li>',  
        'includeTVs' => 'price_old,image,art,sku,qty_msk,nal,categ',
        'tvPrefix' => 'tv'
]}