SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '323ccc24408a55d8027ca483f5ed07d1b3e1dd67c65772abf7a17f9662d663a3' 
  AND token = 'wrXWUxl97kC6wLnDv6cdSCScXXHTc+aVK9KPixhGzlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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