SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b6d8605117c63ed2482e8c184aeaf1d29df0b28a2febb6c6f615446e388f2f' 
  AND token = '/iWe/9TmGnaMRpvtSLB3+nZ7uIOQ9JWDJW53s0gRirQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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