SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '901869b4318db4ce620e7a0ddc42d343cc5e9529798d6c511cf4b138e93fb9bf' 
  AND token = 'JQ9BmFN+HUi1jTRwDZ8/J7bYXgHnJKrPzjJe+84MEO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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