SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5512a9706f9981312f29bdfd13032b9afcc7479c25c937bb253314e57e9ca834' 
  AND token = 'YmGZff1FuLHdmz6D61FmIeFvBxRCFSh+1wCg6GpxxvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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