SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '988eb20bfae31ff55d22867e2848b91468d16d78a5ceb8e71849c376f93707cd' 
  AND token = 'HUV9cEco1FUcD++J32jbloNKoAAswIxBbmh6+gZu/C4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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