SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a8f89db673af422409109b69b8fc2887cc79dd1feaa95d2cbaf8f78d3c93679' 
  AND token = 'hxgyCx6AAbfaZSAZ6xlKll9Gpv2GcVIQF2lGbxwBfDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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