SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b2664db34a9bdd686da890ef780515183f6b448475d437c096caa68225cb0890' 
  AND token = 'xiY0skzJ3pMQaQ0JZdDO1olazpAEwWZ1OibpqTpB5hI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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