SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cbf807933afe30e8478aebb3259d2781fcb236c6b8df71022a353cebac67824c' 
  AND token = 'uyoKUWgQ8zssX6plFiCxm9HCA+LX0m/suy0IZcowYmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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