SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eabf25cd6fc84aefa77ced3d71f548bf0a450ca9e99af3ef3d012a7f57f1d14' 
  AND token = 'd7r4HJ1oBQ4z8c+LhLemTtxxzIOStdLlP+ccvr9AGw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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