SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae5f93e679ee5f1ca22ebf1e4d75a17d0ec5994de66d093a6adf5c56d951595d' 
  AND token = 'xdefex0ZtCvZRs3ncx+aZ42VfhWSsbJ35R09bahULrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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