SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a856844c53daec493078069b83143b897d17267998434a7cbbc38dc73defa573' 
  AND token = 'PF3VgvIm+dI/7Gei0wE71DobSBkjDorf7Io5eUMcsU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

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