SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f390bcee2616dc9e00334bf8fe6863092dd087c222cec00a80f7f00a9a8d922' 
  AND token = '9u6KVj5+LyNm3VuUzwRKb3JBEmKjRGjS0859FWEqjYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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