SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '332fc29fea4944166f71fbd3d952b1c0f6db72008a99570603c7256aad63f277' 
  AND token = 'eQSvK7mIlJeBJO/wo0SkENPWH0pp/9YBnEDjiPHwoNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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