SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '531ffaa45f4f5579444defb9de350b8978b8e945282b492dfae923b951d9627f' 
  AND token = 'O+SC0jUH4My16PsrsDTTAQ0+4VUnZY4F6tlA43/dxi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

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