SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e589505d17da8e05393d5d774418d423560be444d2c8742f524a44e661f4c914' 
  AND token = 'WgjxbPpP61hOiq51DCrvIvZ0F7zH+chzNWVHgMrm/VI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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