Mysql – Should I redesign the “events” table

My system needs to store an append only log of events. Currently I have a database table that stores all the relevant data in one table:

CREATE TABLE `events` (
        `event_id` VARCHAR(255) NOT NULL PRIMARY KEY,
        `event_type` VARCHAR(255) NOT NULL,
        `event_timestamp` DATETIME,
        `group_id` VARCHAR(255),
        `person_id` VARCHAR(255),
        `client_id` VARCHAR(255),
        `name` VARCHAR(768),
        `result` VARCHAR(255),
        `status` VARCHAR(255),
        `logged_at` DATETIME,
        `severity` VARCHAR(255),
        `message` LONGTEXT,
        INDEX `event_type_index` (`event_type`),
        INDEX `event_timestamp_index` (`event_timestamp`),
        INDEX `group_id_index` (`group_id`),
        INDEX `person_id_index` (`person_id`),
        INDEX `client_id_index` (`client_id`),
        INDEX `name_index` (`name`),
        INDEX `result_index` (`result`),
        INDEX `status_index` (`status`),
        INDEX `logged_at_index` (`logged_at`),
      ) ENGINE=InnoDB DEFAULT CHARACTER SET=utf8mb4 COLLATE=utf8_general_ci

But I've noticed that queries with multiple attributes in the WHERE clause are still slow. For example:

SELECT
  count(e.event_id) as total
FROM events e
WHERE
  e.result='Success' AND
  e.event_type='some_silly_event' AND
  e.event_timestamp > '2019-01-01 00:00:00'

One solution would be to create an index like the following:

CREATE INDEX successful_silly_events
ON events (result,event_type,event_timestamp); 

The downsides of this approach seem to be that creating the index would take a long time, and would only speed up this query. If I create a different query on this table with different columns, I'm back to square one.

Would I have been better served by splitting the events table into multiple tables from the start? For example:

CREATE TABLE `events` (
        `event_id` VARCHAR(255) NOT NULL,
        `logged_at` DATETIME,
        `severity` VARCHAR(255),
        `message` LONGTEXT,
        PRIMARY KEY (event_id),
        INDEX `logged_at_index` (`logged_at`),
      ) ENGINE=InnoDB DEFAULT CHARACTER SET=utf8mb4 COLLATE=utf8_general_ci

CREATE TABLE `event_types` (
        `event_id` VARCHAR(255) NOT NULL,
        `event_type` VARCHAR(255) NOT NULL,
        PRIMARY KEY event_id REFERENCES events(event_id)
        INDEX `event_type_index` (`event_type`),
      ) ENGINE=InnoDB DEFAULT CHARACTER SET=utf8mb4 COLLATE=utf8_general_ci

CREATE TABLE `event_timestamps` (
        `event_id` VARCHAR(255) NOT NULL,
        `event_timestamp` VARCHAR(255) NOT NULL,
        PRIMARY KEY event_id REFERENCES events(event_id)
        INDEX `event_timestamp_index` (`event_timestamp`),
      ) ENGINE=InnoDB DEFAULT CHARACTER SET=utf8mb4 COLLATE=utf8_general_ci

CREATE TABLE `event_groups` (
        `event_id` VARCHAR(255) NOT NULL,
        `group_id` VARCHAR(255) NOT NULL,
        PRIMARY KEY event_id REFERENCES events(event_id)
        INDEX `group_id_index` (`group_id`),
      ) ENGINE=InnoDB DEFAULT CHARACTER SET=utf8mb4 COLLATE=utf8_general_ci

And so on for all the other event attributes which I would have normally indexed on the events table. This way, I could construct a similar query:

SELECT
  count(e.event_id) as total
FROM events e
  LEFT JOIN event_results er ON e.event_id=er.event_id
  LEFT JOIN event_types ety ON e.event_id=et.event_id
  LEFT JOIN event_timestamps eti ON e.event_id=et.event_id 
WHERE
  er.result='Success' AND
  ety.event_type='some_silly_event' AND
  eti.event_timestamp > '2019-01-01 00:00:00'

Would the resulting query be fast and not require full table scan? If so, this seems like a better setup.