SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c20f3053b013d640657ec499a47cfb10c8b86e8f47c3dbd8b40d307eac3acf' 
  AND token = 'tUo/Pj/JRx40LVzH1IG1TQmWzWvwrBpvV9I4QCJo0Yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

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