SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeea12a3b62f041867e2d90b52c365f05c92920fc5bbd244fabbd163275d8398' 
  AND token = 'f1vMrKd2WcnRuRSSXxXpDce7uYaVcTAsXBsfjwYtzUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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