SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad192a74a4a604bbeccbc819ec61d93db41b74b11b4c480981622b52bf4a2471' 
  AND token = 'S9pnrrSmvQnvaaL7oExVSBC85vGRG8FC6xwB8qSDtVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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