SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9246e4a6239ac0e2fe430f73382e94efc37c9db429c8a9674ee2448fd55971c' 
  AND token = 'ah4V0hEyv3bHmnpHcJGIEtdWzy7/CJ/SAAkLVR9GXkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

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