SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3da9824ae956e926314d53dce4f45fc51463947950e8e2302d31fa3ec2914807' 
  AND token = '+GgJEtBQUVSkKARs/WxIjVFCaN4/5GWL8ZBs1zqDPok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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