SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '727ecfae1e49dad3289d1b46fbde6ec1fb2cc875b8a8973c28bc7e93a77ee51f' 
  AND token = 'IEURzJz6FDPVCHkFZsZuMyCkLY1qPh09Bdc9qlTmZ7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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