SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4ce47ddba9eccc6e2f8bd0a928c50027f76859907f84bcd9ab29f6a35cbdcaf' 
  AND token = 'N6qgpMSV0o2mOfaaJjQ2qc4onWHB8RE2s+eZ+A5QZVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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