SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce576e83b387754ef5dfde21c5212907e541d0637969655e8b756c0cce999ab7' 
  AND token = '8wuQ2I51JXpBAIqiGW9T9v+YxPcPArqpvxV2GigxYrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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