SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a668d7df77418fdaa0a4ad3cccd6a867134694beada4cae9d7eb6f4dd3664c30' 
  AND token = 'RdTdT9k6EMhDzUpneAWTaGRcTplJcAEIkrdsUsHJVSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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