SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8b4dd0a54043e8b8ee84b12f0113461a2d972b8bb5ae4c1279b5a2f25eba86' 
  AND token = 'YlJhtzoNIamqPsr4AyBEyvJKXt82OjG/YtJQfnhuC2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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