SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cd617a894dd2fca54afbff84694b95f03295a89ca6b185aaa677efacd4f972b' 
  AND token = '+XDOFFNxiP7PmrXhomX+XRvoXclfLAYTRmMXU0S9LKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}