SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '46753fe09af9456820f094389631b466397e07670994e19d3eec7a99eb3cdd05' 
  AND token = 'Cdhs53WPsmSgUQbj2lM7DqhH0dqTuimqyfArBHBOrjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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