SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7939823235fb6b1a898f61f78db9d883ab685b82d4a425faf99df64e9f8d2cb2' 
  AND token = 'eTJTG3UO3qGtPWcQ4+bFO8tSWP8ZWPa+J/XZHZHbOwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

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