SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a43cb9511e34160e7d99f8d7b8410fdab68bb4f7a6604da151595d027665bc47' 
  AND token = 'vj0p/OAa8DNY6s7F8/Yz9fegbiwhXwiQywZvtlZ/iV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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