SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b3d1b565367a147226f9c53099cf17e5089de20dee3db3662f348f4adb3974' 
  AND token = '+phzkBkh2T7mU55qsLMeAlpEIKUl8JpcZJB+cKHsbQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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