SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd88dcc3d947c64b550577a563f323cd6c313f93b5bdbffa1f427a2d964540914' 
  AND token = 'iBQ4+e/MK9c4J6IsmB7YBB8Z6+ke6lUvHl8gP0F7HKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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