SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9955bb696111d738a4b9e42579c65eadd4f62c8b689abca32de0a674031cf34' 
  AND token = 'ZdhZ6Glyv2k8UP6vZ27VGZTzLStjbnMDQYMczpRDrJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}