SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97816e7a427ad64630cb73438e413551132fb8f848f71367b9368428cc640b96' 
  AND token = '9GB1WzHmqg8CCwXM223wXxOk+n9IKuUfvho4hSAb3Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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