SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72c0f62510f03cbaece467318080b13946fb5b7b221cf0f3b187683507898d8b' 
  AND token = 'lHm0vuiDx/PqahryBYklLrlCn4CEZtEGimMlXEFUJZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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