SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6bc3620ff1c9583481db3e9b2962d9b2284c3c09ad9638cc624f86aa04a0cad8' 
  AND token = 'BEmO1ZYI3F6YxO8bSXSWmKZxujk52lDBNKJgJeWrlVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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