具有多个“主键”列的数组

I create an array like this:

$table = Array();
array_push($table, Array('item' => 1, 'storage' = 1, 'qtd' = 0) );
array_push($table, Array('item' => 1, 'storage' = 2, 'qtd' = 4) );
array_push($table, Array('item' => 2, 'storage' = 1, 'qtd' = 78) );
array_push($table, Array('item' => 3, 'storage' = 2, 'qtd' = 10) );

I need to search if i have some item in some storage.. For example in a sql query i do like "... where item = 1 and storage = 2"

How can i search that way in the array, to get the "qtd" value?

Thanks!

$table = Array();

//populate $table array this way
$table[1]=array('item' => 1, 'storage' = 1, 'qtd' = 0);
$table[1]=array('item' => 1, 'storage' = 2, 'qtd' = 4);
$table[2]=array('item' => 2, 'storage' = 1, 'qtd' = 78);
$table[3]=array('item' => 3, 'storage' = 2, 'qtd' = 10);

//to prevent over-writting use in_array() function
if(!in_array(1 /*item*/ ,array_keys($table))){
    $table[1]=array('item' => 1, 'storage' = 1, 'qtd' = 0);
}

//the following will not be inserted as we have already a value at index=1
if(!in_array(1,array_keys($table)),){
    $table[1]=array('item' => 1, 'storage' = 2, 'qtd' = 4);
}     

EDITED**** to get highest max index in $table array

$current_primary_key =   max(array_keys($table));
$next_primary_key = $current_primary_key + 1;

Using the suggestion of alamnaryab, i change to something like this, that works for me:

$table = Array();

$table[1][1]=array('qtd' => 0);
$table[1][2]=array('qtd' => 4);
$table[2][1]=array('qtd' => 78);
$table[3][2]=array('qtd' => 10);

if (!isset($table[1][2]))
{
    echo "Dosent Exists";
}
else
{
    echo "exists. qtd: " . $table[1][2]['qtd'];
}