SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99954fafa0faf54e173b0f7da4646883496072192c9b624c10e3a5fd6c2a658c' 
  AND token = 'WtVSJcLIVF3l4S6Ri39o0UCOIjZZeowgoBJE3qLK8zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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