SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f788120492dbfa9e7131df0f6ddd517b27c7d690ac5068234e553c2f9c0210d' 
  AND token = 'QFSZcQ/cEj8g7rBLEqTeePRy2FUYd/AnGXXTsnkB7kY=' 
  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