SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'eede0ad7379f989d60f1bfca17ce9fd740cc6405cfb28750f7af8b94aff3d29e' 
  AND token = '5phI0UtolmyzmmvidXxbocN7BTVMXoVCJekXa6WmGs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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