SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a76fa70df693bd5f7896f11bbe0820c9913614e22e7c471193b3d70e645b31b' 
  AND token = 'SE6qnaHBw/pHCa5EEfMT2g0XPsT2lNPdZpG21KBKCJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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