SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'abf9a3d95e92105b8353e3e81dd55da4e7d5de5ac2941a49ed82dd8019898085' 
  AND token = '1d8qAh3oDHgiiUyXMNtNBHhe33L3B+nw2tmmLIm3hGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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