SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c4773ca34209fb4887bb5fd5f70fc8d7ad317304cbd510336971b894232fd620' 
  AND token = 'YVkutZ55o3wrH1agn3tmWIAVdUk2Zrd2r5BTkGNriwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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