SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '77a97c91653a50d33455a24dcce638c2e612d141a963aeccbd50032f1cc0a4a7' 
  AND token = 'BpNKqVnoB79GRehyRiJKJJlgtClHM9M1yj7gViBqOec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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