SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76a58f7b2aa0c8c42ab5f64ada45f7cef4566cb9c4282d0671d3414b6fe8231c' 
  AND token = 'JGFKeFpjrIXdCJHOpJ0WVWXRIA4yEC2MKGklr9AWIWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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