SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1332042f428eef2df78e355775bf24338abe6d6349d1c335c24c08a91707ee89' 
  AND token = 'RXT2qiRtJzz1ZOn0PyucuGXwIemmTTQA8DoNcQbTvIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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