SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d98f541a42ddf99f3509baa94801b529698cc1ba16ee39242c20e917bff5bdb' 
  AND token = 'dAjPWUOw8XlJ6+B72jFWHZzPzC+g1wkOeP0Nvl4XMfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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