SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c982e1416e04ca7e3b76ef1355d7e9dbdba01b351986cdca2a6672dec9a25465' 
  AND token = 'PMH7AgnI0Dy+NkjHMZMQqwc3qV91wKb9djmVCE9hinM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables