CODE EXAMPLE FOR PHP

meta_value wordpress

$meta_query_args = array(
    'relation' => 'OR', // Optional, defaults to "AND"
    array(
        'key'     => '_my_custom_key',
        'value'   => 'Value I am looking for',
        'compare' => '='
    )
);
$meta_query = new WP_Meta_Query( $meta_query_args );