SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2950027288cc6a557f31eaa060da7dd9a511d8cca7c443dd4e482bbed35949b4' 
  AND token = 'UIvKwkNbbi2BZ14v3HrYbrj+g+mDwm/llENPPTLeAVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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