SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8421c6cf0aaf05a79d688db3dc43eca15eacc2a7eb6e561cb8866fe3d4476ea8' 
  AND token = 'xknZLY+jAJ7qsu370ar8eqnmcAksQyNRpVGwYAmEDBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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