SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69ac6a33a524c94017ad9b3359b06ca4d5234cda149c341bd4cf9d4a8de11f29' 
  AND token = '3QK7UiZqD7jG5qRI7D4Ad/fzxZhgUj1xqHJ3wWgi+E4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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