SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510f09f8bd68b962fb276db63c827d0d781482ad24d237d543e9ee8a5d792fc7' 
  AND token = '/gOi6cmAVexS0tIlKdTcaaNV+VN9l8DH9+ISWp0GJPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

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