SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8483ef3d97a495a257299ecd5550c7a31a7b6614053688769684a332de540aae' 
  AND token = 'WP3u31wV+K4XXrJIMridbaWsQc5mDeCsFtccDME7+C4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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