SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cb8b831c79c5f5ed3ea2f291cd4167ef533bf58a718a3e42363fcae5b022bb3' 
  AND token = '+sx1ykEiQmhwRImP4hWJRLlhCLvSrWXwQRXwQL3PafM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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