SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0dc1e17beba3351c52054894600e8aaaf0027a4a38799c644939a9f367adcc13' 
  AND token = 'c8YSAgtmCvwk8HM5WQ0HOnluo+7/t/xQktcj/UyP+Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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