SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af87e5d9f9376fc0ad20699998b396e366754f00a33c70c23a3f71405bed3cdb' 
  AND token = 'Yijs19ALoA68mroRtJy8+/FB860sL7jiBPvB5zwbMBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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