SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62a0c3b23cb11578e26a6c5f9975d0e16933fc9cf1f65caed718bdffcf5fd014' 
  AND token = '4Wdy1sYyWn0D66xvRjz/4VnYU+BasxS/jYLbwcednUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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