SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2def40f850810acc5c20cfb58c76710faef68cdde82760bc245705db611dd47f' 
  AND token = 'kVK8uXmjT/h/Q9PKAs+tGJ66BUfMBYuGRIG+9PtBhGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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