SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e58fca29c14577f3fba7676a7bbaf65884564415f3695eda4b5e756ef72fee7a' 
  AND token = 'WxA9p49lK5Osy5IXFGWrBLzc392i7QPMp889JU3ustA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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