SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91ecbdc5e765f769211d1435e76ea44289f55fd7ecb5cd96a6344bb8503187dc' 
  AND token = 'm3CV7MvVdNKTziWpMxWCzqKBdtXhtuoyVndRhC58tUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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