SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd263a1f768da818037540fc687edc24c45b4589027795ab00591187405a74079' 
  AND token = 'ESjyprMK7ZsWiqVRnWicQU2FlyMzt0XUhreTyWQ5PD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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