SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b59d73ab19377631b8fdb97666b1c0cc9aefb1d7e6371631acb7580a7360c6' 
  AND token = 'B9YuTVQa/S2ItI2HhNfgmx2PUZhfd6ycYLLWm8n2Mfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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