<?php
//The values in this arrays contains the names of the indexes (keys) that should exist in the data array
$required = array('key1', 'key2', 'key30' );
$data = array(
'key1' => 10,
'key2' => 20,
'key3' => 30,
'key4' => 40
);
if(count(array_intersect_key(array_flip($required), $data)) === count($required)) {
echo "all exist";
}