SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a724d334a48b980b3d04ab0b71efc286cda1f3d9d688fff07757ef322ed20393' 
  AND token = '2azKJtk8r2B8XMk9dDhk/hVgHLvuK7UZeq66h/FOBUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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