SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b61098bdb71c6c04cba01ae8f10514799b9d957ddd5b51230124d0c2f27e048' 
  AND token = 'KxvsAuwdgNybt647fWh/H2JpN9MhMKhvVEqRVDmyZVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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