SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa631ed733bc0eb15430e220813fad3575fd01b6d4f703e23f230ba802641675' 
  AND token = 'jWLaWq83hReuqeI42VHPyHHTktuUtxbrjpZYOuGCW6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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