SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '307e54f20e488fd88fdd064b846e7e1d500790d9a73b8ecf432847256b9c3d3c' 
  AND token = 'OcatCsfurktlJiuwTO08+YqRk0IgmenHM7Vbz8/YMMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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