SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6dca8aa75388183df58442e79fe6917367192b1c17b5e7186c77d36b9976be0' 
  AND token = '6LtPCl8dNqhzd+IhnHQsDPSiVPayF46bIhGPkUh7R2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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