SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446ca7839b3fd8621153b55698fea86f72589de9b86dbc78df90e273fb023572' 
  AND token = 'U1oJZoXhiB9iN5txZxwqmKnyprcMX7TYhsZzw/uaE+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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