You can include meta_query parametr in your WP_Query.
'meta_query' => array(
'relation' => 'OR',
array(
'key' => 'country',
'value' => 'value',
'compare' => 'LIKE',
),
array(
'key' => 'city',
'value' => 'value',
'compare' => 'LIKE',
),
),