<?php

// your code goes here

$arr = array(1 => 'bar', 2 => 'bin', 3 => 'ipsum', 4 =>'hz');
$foundUnicIds = array(2, 4);

$intersect = array_intersect_key($arr, array_flip($foundUnicIds));
$result = array_values($intersect);

print_r($result);