SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a007372ea734df231d6d9f100bb19e95db34571cd4fdcb38898d5ab89b23e76' 
  AND token = 'vkWrTSMULWigBLCcXQQiKE3nmquPuDvBFtqJfyX/FIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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