SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a44848b761289b45c5285293d53ad343b6d5a59a21301f43695726f95c838ff' 
  AND token = 'SMT7SObx/whgbQmBP2V9Dwr7QrigtuI5HgiUJTpAGfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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