SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b631d53a2415e4cedafa71a9b0fc65d5b356141d152eab421c0eaa002c8b71c7' 
  AND token = 'cKnqw+07ycBAsW46jPcutdUnpMHYnZomUyV7UWD59Wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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