SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d6eb261c1c20fb9117a28ee1e372fdb192660cdebc7da1d18bc431e59188afd' 
  AND token = '3Kds6pHGanSv4ZWOqq00eKhWOisXwPEm/E/1uMpDObw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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