SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8741ff23b5883dcea13f76de4fb81ce3bef2a7812b09ddf501bdff589147f2' 
  AND token = 'ANdcHnrN71oskRPmwDa8JgJzZg42OmzQBqDUOq+6m+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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