SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ccd1297e5da8c7bbb92419d7903748d22dab88acf3b80e493d1b1949fe175234' 
  AND token = 'UMnSS3nLfM7et+Zx/btvZDAa/+NIfsBUd4bjLrnH3Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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