SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fd6688559623d0dc0f4a29c1163f74f439659401b9480d78da65f633f74bb71' 
  AND token = 'Zny1RwJsByzKPswQvOxmgtsK9T7rZqtKdemsJwBphRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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