SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17a2689c6869ea78e42d72edc81cabf20ee370acde574369697ccbddb7726ef4' 
  AND token = 'rEAPB68Jk2MpQWrVKmZJMGJWnmKdnLTGdDhEtTHvS7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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