SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6cdb17001b3c180d190728992ba8ad72983b18a7e438cc106c409e4c913516f' 
  AND token = '0gHrZhwIn3M7tmCK0mRW4eS5lQhV+K1Efgxn1NLi8CQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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