SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f5148d9935327ad0d95bd1c21d3197dc233cafcdd7cd5ee6bf2121d73b8f96' 
  AND token = 'f7KoYxPu8IovP3twsI1ShFA/MYfM6KvLuQzvEhGx0sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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