SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71bdfb86e2336bbd287528e520ae877229eba36fea358b31d03dc71536ed6bb8' 
  AND token = 'BITvxJuabRxovg/gIoLwX3Bu0iaczdPhDKi/r/eRXLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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