SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '501ba84fed70eb6affea88156bae9f9729193ff0fbf1badde08673b3d9c5b323' 
  AND token = 'BmehjNlsSw3oplF8P1ZaiRJFF47o1lIZPKBAqcuQ18k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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