SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8539285a6aa0856258565f78df9a4cd42fa47c125c67b275fda6aa1b8e95f047' 
  AND token = 'Ln9vsnBUfidsKvIYa9REOpDCUY2LBFmV6T5nq+Q8DnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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