SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90d3b53ac6211658e319fd20dd10848416733037d871acc4ad9d8f001409f8c7' 
  AND token = 'ZDgMS8QAq7UfluNYIUcXqxuZfkQxA0keliBw3VtpRv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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