SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '238bb274f1bda4de1fba5d92f8e171cc542617645d2263a957b5cd248b255a71' 
  AND token = 'kqVXr0DjQFi4vp30yOhfAPEpgVZNBkEnFsudDw4tq14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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