SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3617dfe857dffa30f5d990d1181a920398c20c636c9af5ee442fd737fb024c6f' 
  AND token = 'gwTMihgjZuQdLwA8pPxhgUeZoJ1cjrxW3z2j+EaNOxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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