SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '612b44b2a4a2966181fd9b42436ff61cc7f240d59e93ddc59d7ff96e4e8e48ae' 
  AND token = 't00J+C3w/Gud7UJhD6zWVH9qqbqKQxtpL5rxax6SEvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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