SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b6e51b130f5fd190a46fb66652edd87d21369cc80c32fa5128b6fcef39fd00a3' 
  AND token = '3niSzbXbI4OozPGEERgTIi5Rhwfq8BgrW3KCyjm+poY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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