<?php

$array1 = [50, 100];
$array2 = [10, 30, 50, 70, 100];

$isArrayOk = isMyArrayOk($array1, $array2);


function isMyArrayOk($array1, $array2) {

    foreach($array1 as $item) {

		$isOk = false;

        foreach($array2 as $value) {
            if ($item == $value) {
                $isOk = true;
            }
        }

		if($isOk == false){
			return 'not okey';

		}
    }

     return 'ok';
}

echo $isArrayOk;