SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6df088a88ac9e363efdefc802ddc1d3e6b8f1191548a6eab4f1b1e2b59007c2f' 
  AND token = 'rQ3pzpIu85Mh1Wa1zSnyErNAR81EYOGw3jO+EsGz6fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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