SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9b33eea4bf7859636d11b329dc874ac9df167dabda249f18466526f4cbe136e' 
  AND token = '8UQAfCOmliQHM/b7S2yzwN+SDBGFXzJLOXowW0lOx+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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