SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b44b135067d481c239403099bc04e5b557b52c04d6a2c5aa5207405abfb3a3e' 
  AND token = '9nH337+rrt1iun0nwnCdNnzlAwZzouJ+Q+yXBGro1XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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