SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0848b5440b4714737b9a578ac5f843fca2a99c5aaefdd694d332f300aa55aa09' 
  AND token = 'Hee+VhoQERVfx9Me/S42TIiaxBePZ/n8KfRSvOJsY0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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