SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f123aaf321c899f3477dc7d37d879b2b2a46cb8b5a5efb8a298ad57ef604cf7' 
  AND token = '2+0P3g/2hf9bNgVqgtirXQmujtOJjVDoDsC3JZuf/ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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