SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73a229bab541fde7096ef07f4145b8dfebc7fdff30420ca86d99093800889717' 
  AND token = 'Oc/s0ztwnWCENMQBCGL8kB+Y5dQbpgOvJyWHbePKpIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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