SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6990b638dea8482f1d5fbc358d5ae60d726553a10bec949cf945c2f58f9bd66a' 
  AND token = 'r8tshm0jPpnUH7/XW4LtPH6uj1pYy7iZqFogLovh1CI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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