SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a46f4f0481f87df0bd6babb6befa8d3d8d6d1e7cab1773eb2bb04828b829149' 
  AND token = 'eOlVsztL6gAPFJ0kqjg84nIuYuzLM53Rl9nzlvQ6u/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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