SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5076bc4c51f787a66caafd9bb847fe3c3d8c3bb0efa5650679fd4a39464ff696' 
  AND token = '7szg8WbNR+LGF/UCmPG5CLJvi84uqzy0dkBdPFGPYg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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