How to search based on local time, accounting for timezones -

i have collection of shops opening hours , want know of them open.

the problem shops located on world.

this find query looks (i use sql example, doesn't matter):

select shops.name  shops  left join shops_openhours on shops_openhours.shopid=shop.id  shops_openhours.day=[day of week]  , shops_openhours.opentime < [now time] ,  shops_openhours.closetime > [now time] 

when store working time in local time can't search because of timezones.

when store working time in utc can't search because of daylight saving time.

some sample records:

query:

select shops.name, shops_openhours.day day_of_week,  shops_openhours.opentime, shops_openhours.closetime shops left join shops_openhours on shops_openhours.shopid=shop.id 

result:

name    day_of_week     opentime    closetime     shop1   'monday'        '09:00'     '18:00' shop1   'tuesday'       '09:00'     '18:00' shop2   'tuesday'       '10:00'     '19:00' shop2   'tuesday'       '10:00'     '19:00' 

sample query (now monday 09:30):

select shops.name  shops left join shops_openhours on shops_openhours.shopid=shop.id  shops_openhours.day='monday'  , shops_openhours.opentime < '09:30' ,  shops_openhours.closetime > '09:30' 

result:

name  shop1