SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdad1f96705bda740a0c325bd1d6a9c93a816e0b7f2723e797ca131a193c7d21' 
  AND token = 'r/KauE6ryhPTdT6ApztaNr/E2cmtWkfov6u72mH//J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

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