SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0728e4d484051187dc962a36dc238545a10af194d9b73d5f5ee1fbbcb406d3f8' 
  AND token = 'TkcZQdb6IVHiCTJ98lQh0jXk59ggiN16UGwo/u7ABME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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