SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8003bf499968bbe4cd88b58cbe9675b10e00d0a9ee3dc2794a778155033e567a' 
  AND token = 'TNinwn4oBYi/lM++xMhtvcHNgQYbYNiP6UvgE3xT0QI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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