SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c763c639c1e58f801b828946186c93dd81475ac6745e253b2cbacb6ba5933c2' 
  AND token = 'UpJFxg8zIhwHTCECBimQxsMdlJEYrJ2GfxKGh+hWQOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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