SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '982c75ff6c00f05b7584f9f8f9ad3f2ae2874defd1031e0ecf8bf058134a55da' 
  AND token = 'bdM9P+IxwCk54ZCeEigREWe+gnxB7Nv9IM7prCkgvvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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