SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76df043b4509c26a6dd6663229c3450860450881abadd2216c54f5f35db081b7' 
  AND token = 'DC/nisCowHAqhQoMNY2fBtmDZjR5JZ5Yw5Y320qiZHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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