SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08226c685e75bf315d91580de45dcb43558d173c85dda4bdc93646d08c0e6017' 
  AND token = 'YnD1xheSgMTmVvj9/yRw3Od7DrSeV0+cfW2uvITtZWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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