SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9670256592bc1154bc7637355d049d9ba8418d1122f4eb1c9a73add6d2dcb183' 
  AND token = 'u+qI8w7IhUMJLbChALY22Eu/AaLbjBhCGH0tqvg6Ac8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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