SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '843090883cae16f7cae7dc3bd0d14cb9ef94de53a0f9010f852d663575330590' 
  AND token = 'YDcUJPMUiSB72RTvJWBtdZYxBAPTSk8azo62BM53soU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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