SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '516c8b3d49ecd66f17e4325d31ed60af1f384bdf30b5c748af6298b6f46f5753' 
  AND token = 'M5INJU/+TybhkO+u54QIn2zshE/62XQr0xgLlXSbscA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

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