SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19fd174129c46600df18f77393160f3736f51deff96a7c3ac0ba17a05c623fcf' 
  AND token = 'S2BMDsK5iAJ46L89fj2ORSqRTKFDLbLm+x/BMlBGud4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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