SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf290898e0c3d222b3e8f98c3b589613a131fffeaba3f769df94144be54551b' 
  AND token = 'Y6SnCA4oNxQLqfm8AQxXVBd/NYvuHfT4JYyHUXLDWtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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