SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4661c8b35bed8f5ae6a3926fbcc800a680939144909b505710e5432c6febd4b2' 
  AND token = 'uNKgpvYNW7BkPxkpi7Y8UlipdYjnnUh0xkvAtsCQiik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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