SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5f9c7332f17f3438488564afa237063406d3317d1cf152eeaade0175a1fb2dd2' 
  AND token = 'm0Q0bLOLEo4y+hvsZUnz3AOKC4MC7Y9GiUX9La9zNg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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