$dizi = array( 
    array('izmir','rize','bursa'), // 0 
    array('ali','veli','deli'), // 1 
    array('bir','iki','üç'), // 2 
    );  

$db =  new D3Linq();
$db->Query("SELECT key  as index,value as deger FROM dizi WHERE  in_array('veli',$value)");

$veri = $db->fetch_array();

echo $veri['index'];