SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '823d836b00bd9ad1e67d2be92144a94ad1fd4c5b54f87f0a3d217f9fb1291c24' 
  AND token = 'epXAhuW0hAJwWlPeXdsdizZcBhehkGRK2vWk+HuRMcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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