How to search map address in custom post type?

You need a meta_query something like this:

$args = array(
    'post_type' => 'shop',
    'meta_query' => array(
        array(
            'key' => 'map-location',
            'value' => 'London',
            'compare' => 'LIKE' // the = operator might work depending on how your data is stored
        ),
    )
);

Note: I am making some assumptions about how ACF stores data.