SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b71bbf18401b4de54d374a6b680fcd7be006a6eb14b4a4c7592e1830d836da8' 
  AND token = '2ZoLf1aUt+kqQEKUqlIVGPbP/1H1urCQrVuWkf2hupo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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