SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24996762cc6cfb9073e6119f13418a823047d7f65eb0c5635c9ccef2dbe3ae37' 
  AND token = 'GQZs1l3hV5caJkLWlL28P/WRkWdCdf+gSqUbgIGkFVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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