SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40a281f561bd50f782148bc8f0322c852a8c0ce914881ad701b47f575938b7ad' 
  AND token = 'tDZc/PpOB3h9Z0dbw/7l6Xg6xaNoWnvzs7XpFKG4wb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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