SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78ddf8d4f9c7db7b9e0ea02ea696c64be76f9321a5ad4d5a9eec989576bf7c9b' 
  AND token = 'LQoYrznuOx0qQWUNCpWgFqDJWNZYwsGrcbPbV0ySoIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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