SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d84d7777ffde6968253745f889a2156e9df9cd095b5b0b50e4f3ec64b956fdc' 
  AND token = 'lpbSwr4REPDgfRCz0qvH9dxCLBpESZyvOWIU6ARJne4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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