SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83bb255dce8e610380c642c69a6ed2c7da4bae9926eef37200df4646ca195f63' 
  AND token = 'OWoFtHM6UrRjlISD6nUeqEUbRjWBH/QnJjoCRhnlasY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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