SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21343dea4158c61dee6214b5fabb57436f4b82944a026ff00d750a6f89b23c7b' 
  AND token = 'wrAPQHerqKLJuWvK1Mqj9FAod/AQzbaY47zePfsduYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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