SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '53d4c203dba9a9d679bc247ca4017dc453dcd3a80df0b7fba83fe5e1703bf0d2' 
  AND token = 'Npt9ngh/vmfZZ4wdI/cjQuNimKyIld0+SnkOSJ+LKI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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