SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3209d9b54042d6b8a28b0310c079353eb940d31f6632222a5c567d105aab81e6' 
  AND token = 'JUVbu57v7H+6Px5dNynIok3pORauaLs5v4ZL1fNhoZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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