SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0539c7c08aae8ded7af85f341474ce8433c7a9b8fdce683283ee0bb582907a22' 
  AND token = 'ymxQ+uVhiZ1uvtMqiV5gLtfa2oqnWmR/XCUZMRVCSTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}