SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98bb6bd72454cf368df11d31c60f639319797f5295268d1b5ea93310cf8a95b9' 
  AND token = 'JZfthqGHxSwdf8O4zGB6KX+mH1BAbYaG3L0rbSi9iL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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