SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f7787abdc863e45ffa33e9e8a234c8b74576f9139e8cf1caf9837fd2cb47e0' 
  AND token = 'UsJMtoQrMFO0c8PpazujznX+zxZGPXqQJFnYkbVPgOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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