SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19f2491492599046eaafc7cb57961a465442c3ee5c999669d977961ddd20e63d' 
  AND token = 'sCMzR4hVSD8CJHufNGeGWWndCAN1BXvu04e6xgNPSiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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