SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad7f4528dd0a166ffecace2d6f731ee05db8193c6c2dfaf8e0b6a40f22960d50' 
  AND token = 'oWS96w5POIO/LVlwYvYpi5jm679V1nBh2Eh7jWhie7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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