SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddce0ab0dca278a433891ab02df5c8aa51111f80aa5120382050115b7ed7803b' 
  AND token = 'KuX6WB4XjHjh64PKZgfpLkxzhpSlliJwyYhdKwiaaOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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