select
p.ID as id,
str_to_date(meta_value, '%d/%m/%Y') as response_deadline_date
from wp_posts p
inner join wp_postmeta pm on p.ID = pm.post_id and pm.meta_key = 'response_deadline_date'
where
p.post_type = 'announcement' and
p.post_status = 'publish' and
str_to_date(meta_value, '%d/%m/%Y') >= curdate()
order by str_to_date(meta_value, '%d/%m/%Y')