SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43befc646a2cee58486c8c4b92168968cc280b5ab9033783516d90de9f93ac75' 
  AND token = '8ImZWNVvtbOkvQQLY9SPU8gD0ElKIJijecVkHKxWeE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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