SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d7e7bd756bc0effe06d5d2ddc98593c8447446f486559e65b26816c86f921d' 
  AND token = 'A7jQfhhQ1lVrnDdRMbmcqjM38QQNa+BL1ITffzXx5Wk=' 
  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