SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2d4358f5f7bb038daa19359c86dd84ebc657548d955fc9234ed6b9344b4b21e' 
  AND token = 'MJodjLnx8CyDdhy36ZmvC/xdQA9gkgmHkdinGJBLpnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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