SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1b97c647994b6530578387026de4221b02f7dded84eaf036416f13af48c7cf5' 
  AND token = 'GdE8nbWaj5nCl0JxuAFikhkqjNMdVPHyl6+wdRogIow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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